Which statement describes a deterministic effect?

Which statement describes a deterministic effect?

• A. They have a threshold; severity increases with dose.
• B. They have no threshold; probability increases with dose.
• C. They depend on exposure duration rather than dose.
• D. They occur only with internal contamination.

Answer: (A)

Deterministic effects occur only after the tissue dose crosses a threshold, and their severity increases as the dose goes up. Below that threshold, the damage may be repairable and no effect is observed; above it, tissue injury becomes apparent and becomes more severe with higher doses. This is why describing a threshold with increasing severity accurately captures a deterministic effect. In contrast, effects that have no threshold and occur with increasing probability describe stochastic (random) effects, not deterministic ones. Also, deterministic effects are not limited to internal contamination; they can arise from external exposure as well, whenever the tissue dose is sufficiently high to cross the threshold.

Deterministic effects occur only after the tissue dose crosses a threshold, and their severity increases as the dose goes up. Below that threshold, the damage may be repairable and no effect is observed; above it, tissue injury becomes apparent and becomes more severe with higher doses. This is why describing a threshold with increasing severity accurately captures a deterministic effect. In contrast, effects that have no threshold and occur with increasing probability describe stochastic (random) effects, not deterministic ones. Also, deterministic effects are not limited to internal contamination; they can arise from external exposure as well, whenever the tissue dose is sufficiently high to cross the threshold.